WordPress MU

I am using WordPress Mu 2.7. One of my blog owners was trying to post an item, and kept getting the error message:
"method not implemented
POST to /blogs/blogname/wp-admin/post.php not supported."

We tried posting the same item removing various sections until we finally eliminated all but one culprit, ie a link with a hyphen in it (!)

Could that be the cause, and is there a solution?

The offending link is:
http://aguanomics.com/2008/12/kill-capitalists.html

Looks like this is mod_security playing its tricks :)

Thanks for that!